The 27-year-old Bangalorean, who drove the ball well and found more than half the fairways missed a lot of greens in regulation and putted less than satisfactorily.

Lahiri was tied 79th after first round and would need a sub-par round to make sure he stays on for weekend action at the Valhalla Golf Club which is playing to 7,458 yards but that was counter balanced with the somewhat soft and receptive greens.

Lahiri, despite struggling on the greens, scrambled well to make pars, of which he had 16. After starting on the tenth, his big mistake of the day came on the 16th, where he double bogeyed and his lone birdie of the day came on the seventh, where he made up for a terrible pitch which he left short with a fine putt.

"It was a struggle out there. I just could not get my putts to fall. I was leaving them short and I didn't have a great day with the irons. Having said that I am happy that I held things together for a 72. I didn't allow frustration or disappointment to get the better of me," said Lahiri.

Former world number one Lee Westwood, who is still searching for his first Major, carded six-under 66 and he shared the lead with two Americans, Kevin Chappell and Ryan Palmer.

Westwood birdied five of his last six holes and moved into shared lead. Westwood had nine birdies, one bogey and one double bogey in his 65.

Tiger Woods, a four-time PGA Championships winner, who made a late decision to tee up, struggled to a two-over 73 and he could well miss the cut.

Rory McIlroy, the British Open winner and hot favourite after winning WGC-Bridgestone last week, put himself in a good position with a 66 that had eight birdies, besides a double bogey on 10th and a bogey on 11th.

It was Lahiri's first full round-of-18 holes since his second round at the British Open in almost 20 days.

"I have to admit that I was a little rusty not having played a full round since the Friday of British Open. I fell ill and weak and have only just recovered. Here also I played only nine holes on each of the practice days. I wanted to conserve energy and I felt fine out there," said Lahiri.

"I am happy I kept it in check, but am not too upset, though I would have been happier if I had managed to convert some of the chances I created,” he added.

Lahiri missed a few birdies on either side of the course.

"I could not get much to fall from around 10-15 feet for birdies, but on the other hand I did well to scramble and make good putts to save par," added Lahiri with a smile.

McIlroy had three birdies and no bogeys in his front nine 33 and he followed that with two painful holes on 10th and 11th. But he quickly put that behind him with a series of four birdies from 12th to 15th and then closed the day with another birdie on 18th.

"I think it just shows where my game is mentally right now, that I was able to do that today (Thursday)," added the Northern Irishman, who ended the day level with American Jim Furyk, Italy's Edoardo Molinari, Swede Henrik Stenson and Englishman Chris Wood.

Thongchai Jaidee, who has played all four Majors this year, shot even par 71 with two birdies on fourth and 13th and two bogeys on ninth and 18th and he was tied 54th.

Kiradech Aphibarnarat and KJ Choi, both carded 72 each, just as Lahiri did, to be tied 79th.

Noh Seung-yul of Korea, former Asian Tour number one, was the best Asian at 11th with a round of three-under 68.

Defending champion Jason Dufner withdrew after 10 holes when he was eight-over because of an aching neck.